Mr. John Below is a mathematics teacher who instructs Advanced Quantitative Reasoning (AQR) and Advanced Placement (AP) Calculus AB. The source details his professional background, noting his start in teaching in 2003 after serving in the US Army, and his current 8-12 Mathematics certification in Texas. It also includes his daily class schedule, with specific courses assigned to different periods, and provides Google Classroom codes for each section. Furthermore, the document outlines procedures for students regarding makeup tests, requiring them to be completed within two weeks of the original date, and gives instructions for signing up for tutorials.